Wearable electronics have received widespread attention in recent years, including electronic contact lenses containing electrical components that provide the lenses with an added functionality. Many applications for electronic contact lenses have been proposed, such as lenses having glucose sensors for diabetic patients (see, for example, U.S. Pat. No. 8,874,182), and lenses containing an electroactive element having a dynamic aperture (see, for example, U.S. Pat. No. 8,215,770). Electronic lenses have potential application for the correction of vision errors, such as myopia control and presbyopia, where a continuous range of focus (i.e. from near distance to far distance) is desired.
Commercially-available contact lenses made from hydrogels are preferred over lenses made from non-hydrogel materials because they are generally more comfortable. Hydrogel contact lenses are typically made by a cast molding process in which a polymerizable composition is dispensed into a contact lens mold and subjected to curing conditions, typically UV light or heat, that cause the monomer mixture to polymerize. The resulting lens is removed from the mold and hydrated to form a hydrogel, which typically comprises from about 20% to 60% water by weight. During the hydration process the lens swells appreciably in size. A non-swelling material, such as electronic components, incorporated into the lens during the curing step can cause uneven swelling of the hydrogel material upon hydration resulting in damaged or distorted lenses that are unsuitable for ophthalmic use.
Additional background publications include U.S. Pat. Pub. No. 2014/0055741, U.S. Pat. Pub. No. 2015/0145155, U.S. Pat. No. 9,176,332, U.S. Pat. Pub. No. 2015/0234204, U.S. Pat. Pub. No. 2015/0036100, U.S. Pat. No. 4,099,859, and PCT Publication No. WO/2014/194431.